The invention is related to shipbuilding and concerns the design of the lower part of the hull of a planing amphibian.
It is known that the lower part of the hull of a planing amphibian can be built to be flat, smooth and stiff (Pat. of France No. 2490178, Int. Cl. B63B,1/18,1982). The lower part of the hull of this invention doesn't allow for the dampening of impacts from the sea-ways or while clearing obstacles on land. The resulting deformations cause great stress along the lengthwise axis of the lower part of the hull and may lead to damage of the lower part of the hull. Besides, the potential for impact of the lower part of the hull with land requires it to be reinforced, hence, to be heavy. The stiffness of the lower part of the hull allows earth and snow to stick to it. The snow becomes ice, thereby making the movement of the amphibian on land very difficult. All of these factors decrease the operational characteristics of the planing amphibian.
The lower part of the hull most similar in the technical sense and in operation to the present invention is the lower part of the hull of the planing amphibian described in the SU Certificate No. 759390, Int.Cl. B63B,1/22, B60 F, 3/00, 1976. The lower part of the hull according to that invention contains a dampened movable hull member symmetrical to the center plane and attached by its front cross-sectional edge to an immovable member, permitting rotation relative to the hinge. Moreover, between the immovable and movable members of the lower part of the hull, there are air vessels which communicate with an air system. The movable member of the lower part of the hull forms a series of movable steps in cross section and is connected flush with the contours of the immovable member. The movable member of the lower part of the hull is a V-shaped plate in cross-section, and the immovable member of the lower part of the hull has a transverse step, to which the transverse hinge for rotating the movable member of the lower part of the hull is attached--the transverse hinge is in the form of an elastic beam which is situated along the front edge of the movable member. The ship-borne borders of the movable member form a longitudinal step.
The deficiency of this lower part of the hull lies in its insufficient dampening features--there may be severe overloads when the amphibian moves over land obstacles. This is the result of placing the dampening member and air vessels on only a part of the immovable external surface. That is why this surface, excluding the protected part, contacts the ground in the stern while going over obstacles. This deficiency requires that the immovable member be strengthened and hence, leads to greater weight. The stress on the lower part of the hull is accentuated by the contact of the hinge with the air system and the construction of the movable member as a V-shaped plate in cross section, increasing the stress along the bend line and requiring strengthening of the V-shaped plate. The demands for structural strength for both the movable and immovable members requires that they be stiff and metallic, and hence, have good wettability. This leads to snow sticking to the lower part of the hull and ice forming on the lower part of the hull after the amphibian moves from water to land, as well as during the stopping of the amphibian after its moving on the land on account of the heating of the lower part due to friction--this makes worse the amphibian's motion qualities, causing the overloading of the motor. In addition, the hinge fastening the front edge of the movable member to the immovable member of the lower part of the hull leads to a longitudinal step, which, when sliding on land or when making a sharp turn, may cause the amphibian to turn over. The stability is impaired.
In addition, the pressure in the air balloon is constant and does not change during the various operations.
There is a need for a better design of the lower part of the hull for a planing amphibian to maximize the performance of the amphibian.
The object of the present invention is to improve the operational features of the amphibian by improving the dampening characteristics of the lower part of the hull, lowering its weight, increasing the stability, and facilitating the movement of the amphibian from a swampy surface to land, and minimizing the amount of freezing on the lower part of the hull.